Airlines and others continue to seek improved techniques for securing their tickets against counterfeiting and against fraudulent duplication and alteration. Because tickets can have substantial values, tickets remain a target for potential counterfeiters and forgers.
Accordingly, features which can be added to documents such as ticket stock and tickets which will prevent or deter their fraudulent alteration and counterfeiting or which will swiftly and easily indicate that forgery or counterfeiting may have occurred regarding such documents are important potential additions to such documents. That is particularly so if the features are of a relatively low cost, do not require special equipment to be associated with their use, do not alter the documents in ways which will interfere with the equipment with which they are normally used, and which can be employed with documents such as tickets which are otherwise conventional.